Thanks! I'd like to be able to figure this kind of thing out on my own -- what's a good reference for this information? I couldn't find any mention of body parts with Dative of Possession in my copy of A&G.

I couldn't find a suitable reference. Maybe I'm wrong. I'm beginning to think that Latin doesn't possess such a dative for parts of the body, as some other languages do.

P.S. My first thought was "caput mihi dolet" ("my head's sore") but that's "dolet" taking a dative. But you do also have "Aliquid mihi in mentem venit" ("something occurred to me/came to my mind") but again the "venit" opens the door to a dative.

Ah -- Dative of Reference, thank you very much. One tricky thing about LL is that it is easy to understand what is going on with just a casual reading, but it really requires close attention to learn these grammar points, which aren't always explicitly called out.